Trains that have recently been brought into service are often equipped with a train information managing apparatus. The train information managing apparatus monitors the operational state of train-mounted devices and controls the operation of each device so that the trains run more comfortably and efficiently and quick recovery can be achieved in the event of a failure occurring in the equipment. The train information managing apparatus is principally composed of a central apparatus and a terminal apparatus. The operational state information output from each device is transmitted to the central apparatus via the terminal apparatus and the central apparatus typically manages and controls the devices on the basis of the operational state information. A control command signal transmitted from the central apparatus to each device, for example, includes device specific data for individually controlling the operation of each device. Devices that have received a control command signal operate in accordance with the device specific data, thereby providing an efficient train service.
In order to improve the reliability of the train information managing apparatus, a train information managing apparatus has been proposed that has a configuration in which the terminal apparatus is duplexed (for example, Patent Literature 1). With the invention described in Patent Literature 1, the duplicated circuits of the systems mutually monitor each other's operations. When the second system operating as a slave detects an abnormality in the first system operating as a master, the second system starts outputting command signals to the device to be controlled (i.e., starts operating as a master) and notifies the first system of the detection of the abnormality. Upon receiving the notification of the detection of the abnormality, the first system stops outputting command signals to the device to be controlled.